This invention relates generally to an intensifier for increasing the pressure in a gas supplied at a relatively low pressure at an input port and exhausted at an increased pressure at an output port. More specifically, the invention relates to an intensifier that utilizes a hydraulic pump to pressurize hydraulic fluid in a bladder-type accumulator to compress a gas within the bladder. A preferred use of the intensifier is to recharge nitrogen tanks on Howitzer guns that are known as equilibrators or recuperators.
Many devices and processes use pressurized gas. One common method of supplying such pressurized gas is through the use of a tank that is filled with a pressurized gas. A valve on the tank permits the delivery of the gas at a high pressure to whatever device is driven by the gas. As the gas is eliminated from the tank, the pressure within the tank declines. After sufficient use, the pressure in the tank is so low that it does not provide gas at an optimal pressure. Eventually, the tank will need to be refilled, or replaced with a full tank. One common method of refilling the spent tanks is to attach them directly to a supply cylinder that is filled with pressurized gas. The pressure difference between the two containers causes gas to flow from the supply cylinder to the tank, eventually filling the tank to the required pressure.
A disadvantage of this method of filling spent tanks is that the tank cannot be filled to a pressure greater than the supply cylinder that it being used to fill it. As the supply cylinder is used, it loses pressure, and cannot be used to fill any spent tanks after its pressure drops to at or near the desired pressure of the tanks. Therefore, much of the gas in the supply cylinders is not utilized, and it is necessary to refill the supply cylinders even though they have pressurized gas remaining in them.
A known method for pressuring gas is the use of a piston and cylinder pump. While such devices are effective in pressurizing the gas, they are often susceptible to either contamination of the gas, or leakage of the gas, around the seals and gaskets that are necessary in such devices.
Therefore, there exists a need for a method and apparatus that permits filling of depleted tanks through the use of supply cylinders, even when the pressure in the supply cylinder is below the desired pressure of the tank. Preferably, the method and apparatus would be resistant to contamination or loss of the compressed gas around gaskets and seals.
The invention is directed to a gas compressor that uses a hydraulic pump and a hydraulic accumulator to compress gases in gas form. The accumulator is divided into a hydraulic chamber and a pneumatic chamber. The pneumatic chamber of the accumulator can be pneumatically connected to a gas supply and a gas receptacle that needs filled. One-way check valves are used to permit the flow of gas from the gas supply to the pneumatic chamber and from the pneumatic chamber to the gas receptacle, but to prevent the flow of gas in the opposite directions. A motor drives the hydraulic pump, which moves pressurized oil into the hydraulic chamber of the accumulator. The pressurized oil within the hydraulic chamber of the accumulator compresses the gas within the pneumatic chamber of the accumulator, forcing the gas into a tank or other receptacle that needs filled. The invention can be used to compress a variety of gases at different flow rates, volumes, and pressures. The hydraulic pump can be driven by a single-phase or three-phase electric motor, or a gas or diesel powered motor.